Transformation of relaxation oscillations



1939. K. SCHLESINGER 2,170,252

TRANSFORMATION OF RELAXATION OSCILLATIONS Filed July 10, 1937 2Sheets-Sheet l //7 venzor:

Aug. 22, 1939- K. SCHLESINGER 2,170,252

TRANSFORMATION OF RELAXATION OSCILLATIONS Filed July 10, 1937 2Sheets-Sheet 2 //7 venfor:

Patented Aug. 22, 1939 UNITED STATES TRANSFORMATION OF RELAXATIONOSCILLATION S Kurt Schlesinger, Berlin, Germany, assignor toRadioaktiengesellschaft D. S. Loewe, Berlin- Steglitz, GermanyApplication July 10, 1937, Serial No. 152,949

In Germany 6 Claims.

The use of transformers for coupling purposes between an amplifyingtube, the grid of which is excited by relaxation oscillations, and thedefiecting plates of a cathode ray tube has already formed subjectmatter of the earlier applications of the applicant Serial Nos. 106,021(now Patent 2,147,559) and 131,689. In the first place it was recognisedas primary condition relative to the transformer that the width of itsfrequency band must have a range which is governed by the number ofrelaxation oscillations per second as lower limit and by the desiredduration of the return as upper limit. Following this it was recognisedthat even a transformer of this nature is only capable of providing alinear deflection if the same constitutes substantially no load on theconnected amplifying tube. This condition is only capable of beingfulfilled by tubes having a small inner resistance, i. e. by three-poletubes,

having a low-ohmic anode resistance shunting the transformer.

Even if these measures are adopted the image area appearing on thescreen is as a rule not satisfactorily rectilinear. Additional finecorrec- 25 tions are still required, which amount in substance to anintegration or differentiation of the potential curve reaching theprimary terminals of the transformer.

In the present application connection systems 30 are set forth by meansof which it is possible to correct the deflecting potential, i. e. tomake the same linear.

In-the drawings, Figs. 1 to 4 show an arrangement according to theinvention, consisting of 35 relaxation generator followed by anamplifier and a step-up transformer and different means for effectingrectilinear deflecting potential.

Fig. 1 shows these means comprising a variable anode resistance of theamplifier,

40 Fig. 2 shows these means comprising an integration circuit consistingof a parallel connection of a condenser and a resistance in series tosaid anode resistance,

Fig.3 shows these means comprising the said 45 integration circuitaccording to the Fig. 2 cmployed at the same time for steadying theanode potential of said amplifier,

Fig. 4 shows these means comprising a variable resistance in series tothe primary winding of said step-up transformer, and

Fig. 5 shows a suitable arrangement of the said transformer.

In Fig. 1 there is shown an operating tube I, with the grid of whichthere is connected 2. condenser 3, which is charged in linear fashion byway of the resistance 2 and is discharged in the known fashion upon eachimage change by means of a discharge tube 4. According to the inventionthe condition that the transformer is practically no load for the tubeis fulfilled by a regulable July 16, 1936 anode resistance 5, which istraversed by the anode current from the battery l3, Whilst the primarywinding la of the transformer is blocked against direct current by meansof a condenser 8. The coils of the secondary winding lb are connected tothe deflecting plates 13a, 13b of the cathode ray tube, its middle pointto the anode 12. By using a small anode resistance 5 the condition maybe fulfilled that the inner resistance of the generator, i. e., theparallel connection of tube I and resistance 5, be smaller than theinput resistance of the transformer. In practice, however, it is foundthat even with the best balancing of 5 there occurs a descent of therectilinear curve due to the ohmic losses in the transformer. It hasalready been set forth in said earlier application Ser. No. 106,021 thata remedy against this is possible by integrating the linear relaxationpotential and by furnishing the transformer with a superposition of theintegrated and the linear relaxation potential. The integration isperformed in principle by condenser charging. In the case of the lastmentioned application this charging is performed in the grid circuit.There then occurs the difiiculty, however, that the two condenserscannot be discharged simultaneously by one discharge tube, and thereoccurs a slowing down of the return curve.

According to the invention, the integration is performed according toFig. 2 in the anode circuit of the tube I. For this purpose a circuitconsisting of a condenser. shunted by a resistance 6 is connected inseries to the anode resistance 5. The time constant of the circuitconsisting of the resistance 6 and the condenser II Resistance 5:5,000ohms,

' Resistance 6:5,000 ohms,

Condenser 11:4 mf., Condenser 8:10 mf., Winding 7a=4,000 turns x 20 mm.Transformation ratio=1:4 to 1:6.

On the other hand also a correction in the opposite sense may benecessary. This condition occurs in the line relaxation oscillator, in'which the steadying elements (like resistance 6 and condensor II in Fig.3) perform an integration and the resistance,.owing to the smaller inputon iron core negative bias of thetube I.

resistance of the transformer, is generally speaking lower than. in thecase of the image relaxation oscillator. In this case, in accordancewith the invention, correction may be performed vby means of a variableresistance N] (Fig. 4) in series to the primary la of the transformer.The practical values in the case of this connection" system were asfollows:

Resistance 5: 3,000 ohms, Resistance 8:0.1 mf.,

Resistance 10:0 to 5,000-ohms with idealcordeflection 7,0 0

An integral correction may also be adjusted in accordance with theinvention by a stronger If the relaxation curve is. integrated accordingto it, there results a parabola in proportion to 15 This corresponds toa tube characteristic with an increasing steepness. As well known, thismay be adjusted by adjusting the amplifying tube in the lower bend.

It is known that the charging of a condenser by way of a resistance isonly linear as long as the charge is a small part of the existingcharging potential. If the charging potential is better utilized, thecharging curve bends a little down. This means a correction in thereverse direction to that capable of being attained with the tube bias.By simultaneous use of both corrections in the circuit of the dischargetube of the relaxation generator and in the amplifying tube the twocorrections again partially compensate each other, the advantage beingobtained of very good utilisation of the existing battery potential.Practical experiment will show which of the stated correcting measuresaccording to the invention require to be employed in each individualcase. Generally in the vertical deflection there is required a tubecorrection by negative bias, whilst in the rapid horizontal deflectionan opposite correction is necessary.

The operating tube is in all cases a three-pole tube having an internalresistance as small as possible. In the above example it had an internalresistance of a few thousand ohms.

The use of five-pole tubes is fundamentally possible, but does notresult in any advantages. Preferably, therefore, in the case offive-pole tubes the screening grid is connected with the anode, wherebythere is obtained the effect of a three-pole tube.

As, owing to condenser 8, the transformer I carries no d.-c. current itmayhave an iron core without air gap and consequently a high inputimpedance. However, still another condition has to be fulfilled at leastby the horizontal (line) deflection transformer. Its frequency, corresponding to a ZOO-line or 400-line image, amounts to 5,000 or 10,000periods. A rap-id return movement during approximately of this lineperiod accordingly requires of the transformerthe transmission of afrequency of a twenty times higher periodicity with full amplitude.Since on the other hand a large impedance and accordingly the use of aniron core is absolutely essential,

this high frequency can be managed only when the secondary of thetransformer has a very small inner capacity.

The push-pull transformer according to Fig. 5

v.has been found convenient for the practical performance of thisrequirement. It is of the ironclad type'and is provided with a primarycoil Ia:

separated by a high-tension insulation 4 supporting the double secondarywinding la, lb.

I claim: r

1. An arrangement for producing the deflecting voltage of saw-tooth waveform for deflecting the cathode ray in cathode ray tubes for televisionand the like comprising a relaxation generator, an amplifienatransformer having a primary winding being connected via a condenser tothe output of said amplifier, and a secondary wind:- ing being connectedwith the deflecting elements of said cathode ray tube, the input of saidamplifier being connected with the saidgenerator, means for integratingthe potential occurring at the output of said amplifier, means forsuperimposing the said integrated potential on the output potential ofthe amplifier.

2. An arrangement forproducing the deflecting voltage of saw-tooth waveform for deflecting the cathode ray in cathode ray tubes for televisionand the like comprising a relaxation generator, an amplifier, atransformer having a primary winding being connected via a condenser tothe output of said amplifier, and a secondary winding being connectedwith the deflecting elements of said cathode ray tube, the input of saidamplifier being connected with the said generator,

means for integrating the potential occurring at the output of saidamplifier, means" for superimposing the said integrated potential on theoutput potential of the amplifier, said amplifier having an anoderesistance being small as compared with the impedance of the saidprimary winding.

3. An arrangement for producing the deflecting voltage of saw-tooth waveform for deflecting the cathode ray in cathode ray tubes for televisionand thelike comprisingarelaxation generator, an amplifier, a transformerhaving'a primary Winding being connected via a condenser A to the outputof said amplifier, and a secondary winding being connected with thedeflecting elements of said cathode ray tube, the input of saidamplifier being connected with the said generator, means for integratingthe potential occurring at the output of said amplifier, means forsuperimposing the said integrated potential on the output potential ofthe amplifier, the anode resistance of said amplifier being small ascompared with the impedance of said primary wind- 4 amplifier beingconnected with the said generator, an integrating circuit consisting ofa condenser shunted by a resistance connected in series to the anoderesistance of the said amplifier for integrating the potential occurringat the output of said amplifier.

5. An arrangement for producing the deflect- 7 ing voltage of saw-toothwave form for deflecting the cathode ray in cathode ray tubes fortelevision and the like comprising a relaxation generator, an amplifier,a transformer having a primary winding being connected via a condenserto the output of said amplifier, and a secondary winding being connectedwith the deflecting elements of said cathode ray tube, the input of saidamplifier being connected with the said generator, an integratingcircuit consisting of a condenser and a resistance, the last mentionedcondenser and said resistance being simultaneously used for filteringthe anode direct current of the said amplifier and for integrating thepotential occurring at the output of said amplifier.

6. An arrangement for producing the deflecting voltage of saw-tooth waveform for deflecting the cathode ray in cathode ray tubes for televisionand the like comprising a relaxation generator, an amplifier, atransformer having a primary winding being connected via a condenser tothe output of said amplifier, and a secondary winding being connectedwith the deflecting elements of said cathode ray tube, the input of saidamplifier beingconnected with the said generator, an integrating circuitconsisting of a condenser shunted by a resistance connected in series tothe anode resistance of the said amplifier for integrating the potentialoccurring at the output of said amplifier, an ohmic variable resistanceconnected in series to the said primary winding.

KURT SCHLESINGER.

